Differential type wheel setting means in signal controlled platen press



Nov. 19, 1963 A. F. HAYEK 3,111,085

DIFFERENTIAL TYPE WHEEL SETTING MEANS IN SIGNAL CONTROLLED PLATEN PRESSFiled May 2, 1962 3 Sheets-Sheet 1 INVENTOR. ARTHUR F. HAYEK FIG. 4BY/7/2/% ATTORNEY.

A. F. HAYEK DIFFERENTIAL TYPE WHEEL SETTING MEANS IN SIGNAL CONTROLLEDPLATEN PRESS Nov. 19, 1963 3 Sheets-Sheet 2 Filed May 2, 1962 Ow v mm mm@W/ ATTORNEY.

Nov. 19, 1963 A. F. HAYEK DIFFERENTIAL TYPE WHEEL SETTING MEANS INSIGNAL CONTROLLED PLATEN PRESS 3 Sheets-Sheet 3 Fi'led May 2, 1962INVENTOR. ARTHUR F. HAYEK BY W745 ATTORNEY.

United States Patent Office 3,111,085 Patented Nov. 19, 1963 3,111,085DIFFERENTIAL TYPE WIEEL ETTING MEANS IN SIGNAL CGNTRGIJLED PLATEN PRESSArthur F. Hayelt, Pleasantville, N.Y., assignor to General Precision,Inc, a corporation of Delaware Filed May 2, 1962, tier. No. 191,944 7Claims. (Cl. 101-93) This invention relates to printers and moreparticularly to rotary line printers which are capable of imprinting amessage, one character at a time per line, in response to coded electricsignals from computers, data processors or any other source capable ofassembling the signal in the required format.

Digital computers and data processors in current use are capable ofextremely high speed operation and rely on this feature for economicfeasibility since they are extremely expensive to construct and operate.In order that the advantages of this high speed be fully realized, theinformation they supply must be recorded or otherwise reduced to ausable form as rapidly as possible.

In many instances the information must be reduced to printed form. Thus,printers capable of a reasonably high speed are required. However,reliability and durability of the printer must not be sacrificed toachieve high speed since a breakdown of the printer will result in acostly stoppage of the computer or processor.

One object of this invention is to provide a printer suitable for usewith high speed digital computers and data processors which has very fewmoving parts.

Another object of this invention is to provide a printer which may beeasily and quickly replaced due to its physi cal configuration.

A further object of the invention is to provide a printer which isreliable in operation and in which the moving parts are not subjected tolarge or destructive shocks and loads.

Yet another object of the invention is to provide a printer which issmall in size, low in weight and which is easily assembled.

Another object of the invention is to provide a printer which employspressure printing and is quiet in operation.

The invention is concerned with a printing mechanism comprising aplurality of tandem connected differentials, means for moving at leastone rotary element of each differential a predetermined distance inresponse to an electric signal, said tandem differentials providing thesum of the movements of said individual elements at one end, rotary typebearing means responsive to the sum of the movements of the individualrotary element whereby said means is positioned to correspond to thesaid sum, a platen means positioned adjacent said type means, and meansresponsive to an electric signal for urging said platen means towardssaid type means after said means has been positioned to correspond tothe sum.

The foregoing and other objects and advantages of the invention willappear more clearly from a consideration of the specification anddrawings wherein one embodiment of the invention is described and shownin detail for illustration purposes only.

In the drawings:

FIGURE 1 is an isometric view of a novel single wheel printerconstructed according to the invention;

FIGURE 2 is a cross-sectional view of the printer shown in FIGURE 1taken along the line 2-2;

FIGURE 3 is a cross-sectional view of the printer shown in FIGURE 1taken along the line 3-3;

FIGURE 4 is a cross-sectional view of the printer shown in FIGURE 1taken along the line 44; and,

FIGURE 5 is a cross-sectional view of the printer shown in FIGURE 1taken along the line 5-5.

The novel printer 1G is shown in FIGURE 1 with its top and front cover11 and 12., respectively, in place. A print wheel drive shaft 13 extendsthrough front cover 12 and is drivingly connected to print wheel 15which turns with shaft 13. An opening 16 formed between top cover 11 andfront cover 12 is adapted to receive a card or tape, not shown, on whicha message is to be printed. The card when inserted passes under an inkedribbon 17 and over a depressing mechanism not shown in this figure whichwhen actuated urges the card and ribbon simul taneously into contactwith the type mounted on the periphery of that portion of Wheel 15 whichoverlies ribbon 17. Thus, an impression of the type which overlies theribbon is made on the card. Neither the ribbon or card advancemechanisms have been shown since both are beyond the scope of thisinvention and a Wide variety of well-known mechanisms may be used. Powerfor operating these mechanisms is available within the printer andshould be used, especially in conjunction with the card advancemechanism which must be of the intermittent type, so that a synchronizedintermittent motion can be obtained to provide for the successiveprinting of characters on the line.

In FIGURE 2 a motor 20 drives a camshaft 21 at constant speed and aplurality of spaced cams 22, 23, 24, 25, 26, 2'7, 28 and 29 aredrivingly mounted for rotation on shaft 21. A plurality of tandemconnected differentials 3136, inclusive, are mounted on a fixed shaft 38which is mounted between a front wall 39 and a rear wall 49.

Each differential includes two bevel gears 41 and 42, and a spiderassembly 43 mounted for free rotation on shaft 38. A shaft 44 on spiderassembly 43 carries another bevel gear 45 which is free to rotate aboutshaft 44 and simultaneously meshes with gears 41 and 42. A cam follower46 is mounted for rotation on the main body portion of spider assembly43 and in the case of differential 32 engages and follows cam 24 whichis mounted on shaft 21. Bevel gears 41 and 42 of adjacent differentialare connected together by a common hub and rotate together. Bevel gear41 of differential 31 has an arm assembly 43a extending normal to itsaxis and arm assembly 43a mounts a cam follower 46a which engages andfollows cam 22. In addition cam followers 46 of differentials 31, 33,34, 35 and 36 engage and follow cams 23, 25, 26, 27 and 28,respectively.

A spur gear 50 is drivingly connected to bevel gear 42 of differential36. Gear 58 meshes with and drives another spur gear 51 of the samepitch and number of teeth which is drivingly mounted on shaft 13. Shaft13 is journaled for rotation in a bearing 53 mounted in an opening infront wall 39 and in a bearing 54 mounted in an opening in a partitionwall 5-6. The end of camshaft 21 remote from motor 261 is supported forrotation in a bearing 57 which is mounted in the same hole in partition56 that w supports bearing 54. Front wall 39, partition 56 and rear wallextend between a bottom plate 59 and top plate 60 to form a rigidsupport structure for the cams, the differentials and their supportshafts.

In order to minimize the effect of backlash from the differentials onshaft 113, a pair of thrust bearings 61 and 62 are arranged on shaft 38to maintain the differentials in intimate contact and a nut 63 isthreaded on shaft 38 so that it engages one side of thrust bearing 61.Thus, nut 63 may be adjusted to increase or decrease the backlash. Caremust be exercised that nut 63 not be tightened too much since it canintroduce too much friction in the difierentials. However, it must betightened enough to eliminate most of the backlash, otherwise theposition of print wheel 15 will be ambiguous.

The cross-section shown in FIGURE 3 illustrates the arrangement of thedifferentials with respect to the cams. This figure shows in particularthe arrangement of differential 32 and cam 24. However, all of thedifferentials, with the exception of 311, as noted previously, areidentical. In addition, the associated cams are similar in many respectsand a detailed explanation of how they differ will be made later.

A solenoid 66 is anchored by a screw 67 to a support bar 6 8 whichextends parallel to camshaft 21. A bracket 70 is attached to solenoid 66by a screw 71 and extends toward spider assembly 43. An extension 72 ofbracket 70 protrudes beyond the end of armature 73 of solenoid 66 andsupports a link 75 which has one end pivotally connected to extension 72by a screw '76 and its other I end pivotally connected to armature 73.

A stop member 78 is attached to the end of extension 72 by a screw 79and limits the movement of link 75 toward the spider assembly 43 andwhen the position of link 75 is controlled by spring 80 and stop 78, asillustrated, detents 82 and 83 prevent spider assembly 43 and camfollower 46 from following cam 24.

Spider assembly 43 and its cam follower 4.6 are urged toward cam 24 by acoil spring 85 which has one end attached to shaft 44 of assembly 43 andits other end attached to an ear 86 which projects from bracket 70.Thus, when solenoid 66 is energized and armature 73 is drawn, againstthe force extertecl by spring 30, into the solenoid, detent 82disengages from detent 83 permitting cam follower 4'6 to follow cam 24.At the end of one complete revolution of cam 24, the detent 83 willengage detent 8 2 and latch the spider assembly if solenoid 655 isdeenergized since the spring 80 will return armature 73 and detent 82 tothe position illustrated.

The spiders and the latching mechanisms for each of the differentialsare identical with that shown and described in FIGURE 3. In addition,the bevel gear 41 of differential 31 is connected to an assembly 43awhich is identical to the spider assembly and carries a follower 4 651which is released in the same manner as in follower 46 shown in FIGURE3-.

However, cams 22-28, inclusive, are not all identical even though theyare all quite similar in many respects. In the embodiment chosen forillustration, earns 22 and 23 are identical and earns 26, 27 and 28 areidentical. Thus, only five different cam shapes are required. Each cammoves its associated follower and assembly a predetermined angulardistance during a first portion of each cycle of rotation; maintains thefollower and assembly stationary during the second portion of eachcycle; and restores the follower and assembly to the original orstarting position during the third and final portion of the cycle. Theproportion of time consumed to complete each of the cycles may varywidely; however, sufficient time must be reserved to perform eachfunction, and since each of the functions takes much less than k of thecycle, great latitude is provided in the cam design.

Cam 22 is designed so that when follower 46a is released and follows thecam, assembly 43a and gear 41 are rotated through 5.625 during the firstportion of any given cycle to provide one unit of movement. Thus gear 50will be rotated a like amount. Carn 23 is identical to cam 22 androtates spider 43 of differential 31 through 5.625" during the firstportion of any given cycle. However, due to the differential action,this movement results in a movement of 11.25 at gear 50 and provides twounits of movement.

Cam 241 will rotate spider assembly 43 of differential 32 through ll.25during the first portion of any cycle when the associated follower 46 isunlatched to provide by differential action a movement of 22.5 or fourunits at gear 50. Cam 25 rotates spider assembly 43 of differential 33through 22.5 during the first portion ofany cycle when its associatedfollower 46 is unlatched and provides by differential action a movementof 45 or eight units at gear 50. Cams 26, 27 and 28 rotate the spiderassemblies 43 of differentials 34, 35 and 36, respectively, through 45during the first portion of any cycle Whenever an associated follower 46is unlatched and each provides via differential action 90 or 116 unitsof movement of gear 50.

It should be noted at this point that the latching mechanism ofdifferentials 3d and 36 are controlled as a unit, thus, cam 27 provides90 or 16 units of movement and cams 26 and 28 together provide or 32units of movement. It is necessary to combine two cams to provide the180 movement, since a cam throw of 90 is not readily obtainable;therefore, two cams and two differentials are utilized to secured thenecessary throw to provide the 180 movement required at gear '50.

The disclosed printer utilizes a parallel binary coded signal toposition the print wheel as a function of the signal. Six parallelconductors convey the signal and are connected to the solenoids so thatthe least significant or first digit controls the solenoid which latchesassembly 43a of differential 31; the next least significant or seconddigit controls the solenoid which latches assembly 43 of differential311; the third and fourth digits control the solenoids which latchassemblies 43 of differentials 32 and 33, respectively; the fifth digitcontrols the solenoid which latches assembly 43 of differential 3 5; andthe sixth digit controls the solenoids which latch the assemblies 43 ofboth differentials 34 and 36.

When the binary code 000001 is applied via the six parallel conductorsonly the solenoid associated with assembly 43a is energized and onlythat assembly is unlatched. Thus gear 41 of differential 31 is rotatedcounterclockwise and since all the other spider assemblies are latched,gear 50 will rotate clockwise 5.625 If the code is 000010 then onlyspider assembly 43 of differential 31 is unlatched and gear '50 willrotate 11.25 counterclockwise. It should be noted that due to thedifferential action the direction of rotation of gear 50 will bereversed for alternate assemblies. Thus, when the binary code 000100 isapplied the spider assembly 43 of differential 32 is rotatedcounterclockwise and gear 50 rotates counterclockwise 22.5 The code001000 unlatches spider 43 of difierential 33 causing gear 50 to rotate45 clockwise; the code 010000 unlatches spider 43 of differential 35causing gear 50 to rotate 90 clockwise; and the code 100000 unlatchesspider 43 of differentials 34- and 36 causing gear 50 to rotate 180counterclockwise. In every instance the assemblies 43 are rotatedcounterclockwise. If the cam followers are arranged to rotate clockwise,the direction of rotation of gear 50 will be reversed in every instance.When the code unlatches more than one assembly simultaneously, the netmovement of gear 50 is the algebraic sum of the individual movements setforth above. A complete table is set forth on the next page giving allof the codes and the printing wheel positions corresponding theretoalong with a suggested arrangement of characters mounted on the wheel.

Table 1 Wheel Position Charao- Binary Wheel Charac- Binary tor CodePosition ter Code A 000011 33 g 100011 B 000010 34 11 100010 001101 35 1101101 D 001100 36 1' 101100 E 001111 37 k 101111 F 001110 38 1 101110 G001001 39 In 101001 H 001000 40 n 101000 I 001011 41 0 101011 I 00101042 p 101010 K 010101 43 q 110101 L 010100 44 1 110100 M 010111 45 8110111 N 010110 46 1; 110110 0 010001 47 11 110001 P 010000 48 v 110000Q 010011 49 w 110011 R 010010 50 1 110010 S 011101 51 y 111101 'I 01110052 z 111100 U 011111 53 1 111111 V 011110 54 2 111110 W 011001 55 3111001 X 011000 56 4 111000 Y 011011 57 111011 Z 011010 58 6 111010 a100101 59 7 000101 b 100100 60 8 000100 0 100111 61 9 000111 (1 10011062 0 000110 e 100001 63 000001 1 100000 04 (blank) 000000 It should benoted that each Wheel position is displaced 5.625 from the next and thatcode 000000 results in no movement of the wheel. This zero or restposition is blank and 63 additional positions each spaced 5.625" fromthe next are provided on the wheel.

Thus far the description has been limited to that structure which, inresponse to a binary coded signal, positions the print wheel 15 so thata preselected character will be placed in the printing position.However, additional structure is provided for displacing a platen sothat the selected character will be imprinted on a paper or strip whichis interposed between the selected character and the platen. Referringagain to FIGURE 2, cam 29 mounted on camshaft 21 engages a cam follower90 which is mounted on and drives an assembly 91 having a shaft 92projecting laterally therefrom. Shaft 92 passes through walls 56 and 39and is rotatably mounted in bearings 94 and 95 which are pressed intoopenings 96 and 97 in walls 56 and 39, respectively.

The cross-sectional view shown in FIGURE 4 shows the arrangement ofshaft 21, cam 29, cam follower 90, assembly 91 and shaft 92 in greaterdetail than the view shown in FIGURE 2. Assembly 91 has a detent 124which engages a similar detent 125 on a lever 126 which is pivotallymounted on a shaft 127. The two detents are maintained in engagement bya spring 93 which exerts a force on lever 126 and by another spring 99'which exerts a force on assembly 91. A solenoid 101 has its armature 102connected to lever 112 6 at the end remote from detent 125 and whenenergized overcomes the force exerted by spring 98 permitting thedetents to disengage. Thus spring 9 9 urges cam follower 90 intoengagement with cam 29 and when the follower encounters the fiat portionof the cam, a large rotation is imparted to shaft 92. This largerotation is used to move the platen located under print wheel 15. If thesignal has been removed from solenoid 101, the two detents under thecoercive forces exerted by springs 98 and 99 will engage after the fiatspot on cam 29' passes cam follower 90.

The voltage for energizing solenoid 101 to unlatch cam follower 90 issupplied in a seventh conductor with the input signal from the computeror data processor. This voltage will provide energization to unlatch thesolenoid so that printing may be completed. An alternative arrangementis possible. Here solenoid '1, lever 126 and spring 93 are eliminatedand follower 90 is permitted to operate shaft 92 each cycle ofoperation. Since wheel position 64 is blank, nothing can be printed whenno signal or code 000000 is present. The modification shown in FIGURE 4,however, provides less wear, longer life, and one additional charactersince the 64th wheel position may contain a character and printing isonly completed in those cycles of operation when a character has beeninserted by the computer.

Printing is accomplished by moving a platen surface under the printwheel 15 toward the selected character which has been positioned at thebottom and urging the inked tape 17 and a piece of paper which has beeninserted into contact with the selected type on the bottom of the wheelthus causing the character to be imprinted on the paper. FIGURE 5illustrates the platen mechanism and shows its structural relationshipto the print wheel 15 and drive shaft 92. Shaft 92 supports and drivesan L-shaped push rod 105 and when rotated counterclockwise lifts theplaten assembly 106 which rides in a vertical guide block 108. Therotation of shaft 92 caused by the throw of cam follower 90 and assembly961 is sufficient to urge the T-shaped platen member 110 of platenassembly 106 into contact with the type 111 mounted on the periphery ofwheel 15.

Assembly 106 comprises a cylindrical body 1'12 having a circular holetherethrough in which T-shaped platen 110 rides. Platen 110 is held inplace by a pin 114 which passes through a slot 115 in the lower bodyportion of the platen and a spring 116 positioned in the hole betweenthe lower end of the platen and a threaded plug 117 which is inserted inthe lower end of the circular hole and completes the support forT-shaped platen 110. Thus, spring 116 and threaded plug 117 provide boththe necessary clearance for the platen and quiet pres-sure printing.

While only one specific embodiment of the invention has been shown anddescribed in detail, it is obvious that many different arrangements maybe made to perform the same functions; therefore, applicant wishes itclearly understood that the invention is not limited to the specificarrangement described and shown in detail for illustration purposes.

What is claimed is:

1. A printing mechanism comprising,

a plurality of tandem connected differentials, each of saiddifferentials having a first and a second bevel gear with the secondbevel gear of each differential connected to the first bevel gear of thenext differential, a spider assembly including at least one bevel gearrotatable thereon and mounted for rotation between the first and secondbevel gears of each differential;

means responsive to a coded electric signal for selectively rotating apredetermined distance the first bevel gear of the first differentialand all of the spider assemblies to provide a rotary output at thesecond bevel gear of the last differential which corresponds to the sumof the individual movements of the spider assemblies and the first bevelgear of the first differential which are moved in response to the codedelectric signal;

type bearing means responsive to said rotary output whereby said typebearing means is positioned to correspond to the coded electric signal;

platen means located adjacent said type bearing means;

and means for urging said platen toward said type bearing means aftersaid type bearing means has been positioned by the rotary output tocorrespond to the coded signal.

2. A printing mechanism as set forth in claim 1 in which the meansresponsive to the coded electric signal for selectively rotating apredetermined distance the first bevel gear of the first differentialand all of the spider assemblies to provide a rotary output at thesecond bevel gear of the last differential comprises,

7 a latched lever arm connected to each of said elements which are to berotated, a cam follower connected to each lever arm, cam meanspositioned for rotation adjacent each of 8 ing a predetermined angularrotation of the lever arm and the rotary element at which it isattached, means for rotating said cam means, and means responsive to thesaid coded electric signal said cam followers, each of said cam meansprov-id- 5 for selectively unlatching the lever arms. ing apredetermined angular rotation of the lever 6. A printing mechanism asdefined in claim 4- in which arm and the rotary element at which it isattached, the means responsive to an electric signal for urging saidmeans for rotating said cam means, platen means toward said type bearingmeans after it has and means responsive to the said coded electricsignal been positioned comprises,

for selectively unlatching the lever arms. 10 a latched pivoted levermeans having a cam follower 3. A printing mechanism as set forth inclaim 1 in attached thereto at one end and engaging said platen whichthe means for urging said platen toward said type means at its otherend, bearing means after said type bearing means has been a cam meansmounted for rotation adjacent said cam positioned by the rotary outputcomprises, follower, said cam means providing movement of a pivotedlever means having a cam follower attached said follower and saidplaten,

thereto at one end and engaging said platen means and means forunlatching said lever in response to the at its other end, said electricsignal so that said cam follower may a cam means mounted for rotationadjacent said cam follow the cam means which provides movement atfollower, said cam means providing movement of a predetermined angulardisplacement which occurs said follower and said platen at apredetermined after the type bearing means has been positioned. angulardisplacement which occurs after the type 7. A printing mechanismcomprising, bearing means has been positioned. a plurality of tandemconnected dilferentials each in- 4. A printing mechanism comprising;eluding at least three rotary elements, a plurality of tandem connecteddifferentials; a latched lever arm connected to at least one rotary eachof said differentials having a first and a second element of eachdifferential,

bevel gear with the second bevel gear of each difa cam followerconnected to each lever arm, ferential connected to the first bevel gearof the next cam means positioned for rotation adjacent each saiddifferential, a spider assembly including at least one cam follower,each of said cam means providing a bevel gear rotatable thereon andmounted for rotapredetermined angular rotation of the lever arm and tionby the first and the second bevel gears of each the connected rotarydifferential element when the diiferential; follower engages the cam andthe cam is rotated, means responsive to a coded electric signal forselecmeans for rotating the cam means,

tively rotating the first bevel gear of the first difmeans responsive toa coded electric signal for selecferential and all of the spiderassemblies a predetively unlatching preselected lever armsin responsetermined distance to provide a rotary output at the to said coded signalto permit the cam followers consecond bevel gear of the lastdilterential which cornected thereto to follow the adjacent cam meansresponds to the sum of the individual movements whereby each unlatchedlever arm rotates its conof the spider assemblies and the first bevelgear of the nected rotary differential element a preselected angufirstdifierential; lar distance to provide a rotary output at one end ofrotary type bearing means responsive to the rotary said tandem connecteddifferentials which corremotion of the said second bevel gear of thelast difsponds to the sum of the angular displacements of the ferentialwhereby said mean i positioned to correrotary elements connected to theunlatched lever spond to the said sum; arms, platen means positionedadjacent said rotary type beartype bearing means responsive to saidrotary output for ing means; assuming a position in accordancetherewith, and means responsive to an electric signal for urging platenmeans PQSitiOned adjacent said yp bearing said platen means toward saidtype bearing means means, and after it has been positioned. meansresponsive to an electric signal for urging said 5. A printing mechanismas set forth in claim 4 in platen means'toward Said yp bearing means f rit which the means responsive to the coded electric signal 59 has beenPositionedfor selectively rotating a predetermined distance the firstbevel gear of the first differential and all of the spider References(Lied m the file of this patgnt assemblies to provide a rotary output atthe second bevel UNITED STATES PATENTS ge r of the last differentialcomprises, 2,077,964 Smith Apr 20, 1937 a latched lever arm connected toeach of said elements 2,077,965 Smith Apr. 20, 1937 which are to berotated, 2,687,087 Crowell Aug. 24, 1954 a cam follower connected toeach lever arm, 2,784,667 Broido Mar. 12, 1957 cam means positioned forrotation adjacent each of 2,867,168 Roth Jan. 6, 1959 said camfollowers, each of said cam means provid- 2, 3 Henri-Collins ag. 59

1. A PRINTING MECHANISM COMPRISING, A PLURALITY OF TANDEM CONNECTEDDIFFERENTIALS, EACH OF SAID DIFFERENTIALS HAVING A FIRST AND A SECONDBEVEL GEAR WITH THE SECOND BEVEL GEAR OF EACH DIFFERENTIAL CONNECTED TOTHE FIRST BEVEL GEAR OF THE NEXT DIFFERENTIAL, A SPIDER ASSEMBLYINCLUDING AT LEAST ONE BEVEL GEAR ROTATABLE THEREON AND MOUNTED FORROTATION BETWEEN THE FIRST AND SECOND BEVEL GEARS OF EACH DIFFERENTIAL;MEANS RESPONSIVE TO A CODED ELECTRIC SIGNAL FOR SELECTIVELY ROTATING APREDETERMINED DISTANCE THE FIRST BEVEL GEAR OF THE FIRST DIFFERENTIALAND ALL OF THE SPIDER ASSEMBLIES TO PROVIDE A ROTARY OUTPUT AT THESECOND BEVEL GEAR OF THE LAST DIFFERENTIAL WHICH CORRESPONDS TO THE SUMOF THE INDIVIDUAL MOVEMENTS OF THE SPIDER ASSEMBLIES AND THE FIRST BEVELGEAR OF THE FIRST DIFFERENTIAL WHICH ARE MOVED IN RESPONSE TO THE CODEDELECTRIC SIGNAL; TYPE BEARING MEANS RESPONSIVE TO SAID ROTARY OUTPUTWHEREBY SAID TYPE BEARING MEANS IS POSITIONED TO CORRESPOND TO THE CODEDELECTRIC SIGNAL; PLATEN MEANS LOCATED ADJACENT SAID TYPE BEARING MEANS;AND MEANS FOR URGING SAID PLATEN TOWARD SAID TYPE BEARING MEANS AFTERSAID TYPE BEARING MEANS HAS BEEN POSITIONED BY THE ROTARY OUTPUT TOCORRESPOND TO THE CODED SIGNAL.